Receiver unit of a wireless power transfer system

ABSTRACT

A receiver unit of a wireless power transfer system is presented. The receiver unit includes a main receiver coil, a plurality of auxiliary receiver coils disposed about a central axis of the main receiver coil, and a receiver drive subunit. The receiver drive subunit includes a main converter operatively coupled to the main receiver coil and having a main output terminal. The receiver drive subunit may include a plurality of auxiliary converters operatively coupled to the plurality of auxiliary receiver coils. The plurality of auxiliary converters may be operatively coupled to each other to form an auxiliary output terminal coupled in series to the main output terminal to form a common output terminal. In some implementations, the receiver drive unit may be formed on a substrate of an integrated electronic component. The integrated electronic component may further include a communication subunit and a controller disposed.

CROSS-REFERENCE TO RELATED APPLICATIONS

This Patent Application claims priority to India Patent ApplicationNumber 201841014948, filed Apr. 19, 2018, entitled “A RECEIVER UNIT OF AWIRELESS POWER TRANSFER SYSTEM AND AN ASSOCIATED METHOD THEREOF” and toIndia Patent Application Number 201843033690, filed Sep. 7, 2018,entitled “INTEGRATED ELECTRONIC COMPONENT OF A RECEIVER UNIT OF AWIRELESS POWER TRANSFER SYSTEM”, the contents of which are herebyincorporated by reference.

TECHNICAL FIELD

Certain aspects of the present disclosure generally relate to a powertransfer system and more particularly to a wireless power transfersystem. In one aspect, the present disclosure relates to a receiver unitof a wireless power transfer system.

DESCRIPTION OF THE RELATED TECHNOLOGY

A wireless power transfer system includes a transmitter coil, a receivercoil, and corresponding electronic circuitry. Typically, efficiency ofpower transfer between the transmitter coil and the receiver coil iscompromised due to misalignment between the transmitter coil and thereceiver coil.

Different techniques have been proposed for overcoming the shortcomingsin power transfer due to misalignment between the transmitter coil andthe receiver coil. Some of these techniques use controllable switches,adaptive controllers, position sensors, and optical cameras, which canresult in a complex power transfer system with associated power losses.Furthermore, the packaging of the electronic circuitry remains achallenge.

Thus, there is a need for an enhanced receiver unit of the wirelesspower transfer system and an associated method.

SUMMARY

Various implementations of systems, methods and devices within the scopeof the appended claims each have several aspects, no single one of whichcan be solely responsible for the desirable attributes described herein.Without limiting the scope of the appended claims, some prominentfeatures can be described herein.

In accordance with one aspect of the present specification, a receiverunit of a wireless power transfer system is presented. The receiver unitincludes a main receiver coil, a plurality of auxiliary receiver coilsdisposed about a central axis of the main receiver coil, and a receiverdrive subunit. The receiver drive subunit includes a main converteroperatively coupled to the main receiver coil, where the main converterincludes a main output terminal. Further, the receiver drive subunitincludes a plurality of auxiliary converters operatively coupled to theplurality of auxiliary receiver coils, where the plurality of auxiliaryconverters is operatively coupled to each other to form an auxiliaryoutput terminal, and where the auxiliary output terminal is coupled inseries to the main output terminal.

In accordance with another aspect of the present specification, awireless power transfer system is presented. The wireless power transfersystem includes a transmitter unit, and a receiver unit operativelycoupled to the transmitter unit. The receiver unit includes a mainreceiver coil, a plurality of auxiliary receiver coils disposed about acentral axis of the main receiver coil, and a receiver drive subunit.The receiver drive subunit includes main converter operatively coupledto the main receiver coil, where the main converter includes a mainoutput terminal; and a plurality of auxiliary converters operativelycoupled to the plurality of auxiliary receiver coils, where theplurality of auxiliary converters is operatively coupled to each otherto form an auxiliary output terminal, and where the auxiliary outputterminal is coupled in series to the main output terminal.

In accordance with another aspect of the present specification, a methodof operation of a receiver unit of a wireless power transfer system. Themethod includes inducing a first voltage at at least one of a mainreceiver coil and a plurality of auxiliary receiver coils based on analignment of the main receiver coil and the plurality of auxiliaryreceiver coils with a transmitter coil. Further, the method includesgenerating a second voltage at a main output terminal of a mainconverter and a third voltage at an auxiliary output terminal of aplurality of auxiliary converters based on the first voltage.Furthermore, the method includes transmitting a combination of thesecond voltage and the third voltage to a load.

In accordance with another aspect of the present specification, areceiver unit of a wireless power transfer system is presented. Thereceiver unit includes a main receiver coil, a plurality of auxiliaryreceiver coils disposed about a central axis of the main receiver coil,and an integrated electronic component. The integrated electroniccomponent includes a substrate, a receiver drive subunit formed on thesubstrate, where the receiver drive subunit includes a main converteroperatively coupled to the main receiver coil, where the main converterincludes a main output terminal and a plurality of auxiliary convertersoperatively coupled to the plurality of auxiliary receiver coils, wherethe plurality of auxiliary converters is operatively coupled to eachother to form an auxiliary output terminal coupled in series to the mainoutput terminal to form a common output terminal. Further, theintegrated electronic component includes a communication subunit formedon the substrate and operatively coupled to the receiver drive subunitand a controller disposed on the substrate and operatively coupled to atleast one of the common output terminal, an alternating current terminalof the main converter, alternating current terminals of the plurality ofauxiliary converters, and the communication subunit, where thecontroller is configured to determine one or more circuit parameterscorresponding to at least one of the common output terminal, thealternating current terminal of the main converter, and the alternatingcurrent terminals of the plurality of auxiliary converters and controlat least the communication subunit based on the one or more circuitparameters.

In accordance with another aspect of the present specification, awireless power transfer system is presented. The wireless power transfersystem includes a transmitter unit, a receiver unit operatively coupledto the transmitter unit, where the receiver unit includes a mainreceiver coil, a plurality of auxiliary receiver coils disposed about acentral axis of the main receiver coil, and an integrated electroniccomponent. The integrated electronic component includes a substrate anda receiver drive subunit formed on the substrate. The receiver drivesubunit includes a main converter operatively coupled to the mainreceiver coil, where the main converter includes a main output terminal;and a plurality of auxiliary converters operatively coupled to theplurality of auxiliary receiver coils, where the plurality of auxiliaryconverters is operatively coupled to each other to form an auxiliaryoutput terminal coupled in series to the main output terminal to form acommon output terminal. The integrated electronic component furtherincludes a communication subunit disposed on the substrate andoperatively coupled to the receiver drive subunit and a controllerdisposed on the substrate and operatively coupled to at least one of thecommon output terminal, an alternating current terminal of the mainconverter, alternating current terminals of the plurality of auxiliaryconverters, and the communication subunit, where the controller isconfigured to determine one or more circuit parameters corresponding toat least one of the common output terminal, the alternating currentterminal of the main converter, and the alternating current terminals ofthe plurality of auxiliary converters and control at least thecommunication subunit based on the one or more circuit parameters.

In accordance with another aspect of the present specification, a methodof operation of a wireless power transfer system is presented. Themethod includes determining, by a controller, one or more circuitparameters corresponding to at least one of a common output terminal, analternating current terminal of a main converter, and alternatingcurrent terminals of a plurality of auxiliary converters, where thecommon output terminal is formed by connecting an auxiliary outputterminal to a main output terminal of the main converter in series,where the auxiliary output terminal is formed by operatively couplingthe plurality of auxiliary converters of a receiver drive subunit toeach other. Further, the method includes controlling operation of acommunication subunit based on the one or more circuit parameters, wherethe communication subunit is operatively coupled to the receiver drivesubunit. Furthermore, the method includes inducing a first voltage, by atransmitter coil of a transmitter unit, at at least one of a mainreceiver coil and a plurality of auxiliary receiver coils based on analignment of the main receiver coil and the plurality of auxiliaryreceiver coils with the transmitter coil, where the plurality ofauxiliary converters is operatively coupled to the plurality ofauxiliary receiver coils and the main converter is operatively coupledto the main receiver coil. Additionally, the method includes generatinga second voltage at the common output terminal.

In accordance with another aspect of the present specification, anintegrated electronic component for a receiver unit of a wireless powertransfer system is presented. The integrated electronic componentincludes a substrate, a receiver drive subunit formed on the substrate,where the receiver drive subunit includes a main converter configured tobe operatively coupled to a main receiver coil, where the main converterincludes a main output terminal; and a plurality of auxiliary convertersconfigured to be operatively coupled to a plurality of auxiliaryreceiver coils, where the plurality of auxiliary converters isoperatively coupled to each other to form an auxiliary output terminalcoupled in series to the main output terminal to form a common outputterminal. Further, the integrated electronic component includes acommunication subunit formed on the substrate and operatively coupled tothe receiver drive subunit. Furthermore, the integrated electroniccomponent includes a controller disposed on the substrate andoperatively coupled to at least one of the receiver drive subunit andthe communication subunit, where the controller is configured todetermine one or more circuit parameters corresponding to the receiverdrive subunit and control at least the communication subunit based onthe one or more circuit parameters.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the presentdisclosure will become better understood when the following detaileddescription is read with reference to the accompanying drawings in whichlike reference numbers and designations represent like elementsthroughout the drawings. Other features, aspects, and advantages willbecome apparent from the description, the drawings, and the claims. Notethat the relative dimensions of the following figures may not be drawnto scale.

FIG. 1A is a block diagram of an example wireless power transfer system.

FIG. 1B is a block diagram of another example wireless power transfersystem.

FIG. 2 is a schematic representation of an example receiver unit.

FIG. 3 is a schematic representation of another example receiver unit.

FIG. 4 is a schematic representation of another example receiver unit.

FIG. 5 is a detailed circuit representation of an example wireless powertransfer system.

FIG. 6 is a detailed circuit representation of another example wirelesspower transfer system.

FIG. 7 is a detailed circuit representation of another example wirelesspower transfer system.

FIG. 8 is a schematic representation of an example wireless powertransfer unit for use in a wireless power transfer system.

FIGS. 9A and 9B are cross-sectional representations of a portion of anexample wireless power transfer unit.

FIG. 10A is a schematic representation of a receiver coil of an examplewireless power transfer system.

FIG. 10B is another schematic representation showing example receivercoils.

DETAILED DESCRIPTION

The following description is directed to certain implementations for thepurposes of describing innovative aspects of this disclosure. However, aperson having ordinary skill in the art will readily recognize that theteachings herein can be applied in a multitude of different ways. Thedescribed implementations can be implemented in any device, system ornetwork that is capable of transmitting and receiving wireless power.

As will be described in detail hereinafter, various embodiments of awireless power transfer (WPT) system are disclosed. In particular, thesystems and methods disclose employing an receiver unit having aplurality of auxiliary receiver coils disposed about a central axis of amain receiver coil. Further, the various embodiments disclose differentarrangements of the auxiliary receiver coils with respect to the mainreceiver coil. Furthermore, the embodiments disclose the arrangement ofthe auxiliary receiver coils with respect to associated auxiliaryconverters. The receiver unit may be employed in wireless chargingsystems, such as but not limited to a mobile phone, a laptop, anelectric vehicle, consumer electronic products, and the like. In someimplementations, the systems and methods disclose the arrangement of thereceiver coils with respect to associated converters. Additionally,different embodiments of the integrated electronic component of thereceiver unit is disclosed.

Particular implementations of the subject matter described in thisdisclosure can be implemented to realize one or more of the followingpotential advantages. In some implementations, the arrangement of themain receiver coil and the plurality of auxiliary receiver coils may aidin enhancing communication with the transmitter coil and allowsefficient power transfer between the transmitter coil and the receivercoils even in the event of misalignment of the main receiver coil withthe transmitter coil. In some implementations, the arrangement of theauxiliary converters may aid in activation and deactivation of thediodes of the auxiliary converters without use of controllers.Furthermore, the wireless power transfer system may adjust misalignmentsbetween the transmitter unit and the receiver unit without employingsensors or any other detection techniques, such as camera. In someimplementations, the main converter, the auxiliary converters, and otherrelated electronics of the receiver unit may be formed on a substrate toform an integrated electronic component. Accordingly, the footprint ofthe corresponding electronics of the receiver unit may be considerablyreduced.

FIG. 1A is a block diagram of an example wireless power transfer system100. The wireless power transfer system 100 includes a wireless powertransfer unit 102 and a power source 104. In the illustrated embodiment,the wireless power transfer unit 102 includes a transmitter unit 106, areceiver unit 108, and a field focusing coil 110. The transmitter unit106 is magnetically coupled to the receiver unit 108 via the fieldfocusing coil 110. The field focusing coil 110 is used to focus amagnetic field from the transmitter unit 106 to the receiver unit 108.In another embodiment, the field focusing coil 110 may not be present inthe wireless power transfer unit 102.

The transmitter unit 106 includes a transmitter (Tx) drive subunit 112coupled to a transmitter (Tx) coil 114. In one embodiment, thetransmitter drive subunit 112 may be a converter. The transmitter drivesubunit 112 includes semiconductor switches, such as an insulated gatebipolar transistor, a metal oxide semiconductor field effect transistor,a field-effect transistor, an injection enhanced gate transistor, anintegrated gate commutated thyristor, a gallium nitride based switch, asilicon carbide based switch, a gallium arsenide based switch, diodes,or the like. In one embodiment, the transmitter coil 114 may be a woundcopper wire.

The receiver unit 108 includes a receiver (Rx) coil 116 and a receiver(Rx) drive subunit 118. In accordance with aspects of the presentspecification, the receiver coil 116 includes a main receiver coil 120and a plurality of auxiliary receiver coils 122. The plurality ofauxiliary receiver coils 122 is disposed about the central axis of themain receiver coil 120. The plurality of auxiliary receiver coils 122may also be interchangeably referred to herein as an array of auxiliaryreceiver coils. In some implementations, each of the main receiver coil120 and the plurality of auxiliary receiver coils 122 may include awound copper wire.

In some implementations, the example receiver unit 108 may form a partof a two-coil wireless power transfer system, three-coil wireless powertransfer system, and a four-coil wireless power transfer system. As willbe appreciated, the two-coil wireless power transfer system includes thereceiver unit and the transmitter unit. Further, the three-coil powertransfer system includes a field focusing coil in addition to thereceiver unit and the transmitter unit. The four-coil power transfersystem includes a phase compensation coil in addition to the receiverunit, the field focusing coil, and the transmitter unit.

In one embodiment, the main receiver coil 120 and the plurality ofauxiliary receiver coils 122 are resonant coils. In particular, each ofthe main receiver coil 120 and the plurality of auxiliary receiver coils122 may be coupled to a corresponding capacitor (not shown). In someimplementations, the main receiver coil 120 and the plurality ofauxiliary receiver coils 122 are compatible with a Wireless PowerConsortium™ (WPC) standard (Qi™) that is defined in a frequency range of100 kHz to 200 kHz.

Further, the receiver drive subunit 118 includes a main converter 124and a plurality of auxiliary converters 126. The main receiver coil 120is coupled to the main converter 124. The main converter 124 includes amain output terminal and is configured to rectify a voltage induced atthe main receiver coil 120 during operation. Each of the main converter124 and the plurality of auxiliary converters 126 include a plurality offirst switches (not shown). The plurality of first switches includessemiconductor switches, such as an insulated gate bipolar transistor, ametal oxide semiconductor field effect transistor, a field-effecttransistor, an injection enhanced gate transistor, an integrated gatecommutated thyristor, a gallium nitride based switch, a silicon carbidebased switch, a gallium arsenide based switch, diodes, or the like.

The main receiver coil 120 is coupled to the main converter 124. Themain converter 124 includes a main output terminal (not shown) and isconfigured to rectify a voltage induced at the main receiver coil 120.Further, the auxiliary receiver coils 122 are coupled to the auxiliaryconverters 126. The auxiliary converters 126 are configured to rectifyvoltages induced at the auxiliary receiver coils 122. In one embodiment,each auxiliary receiver coil 122 is coupled to a corresponding auxiliaryconverter 126. In one embodiment, at least one of the main converter 124and the plurality of auxiliary converters 126 is a passive rectifier. Inone specific embodiment, the passive rectifier is a diode rectifier. Inanother embodiment, at least one of the main converter 124 and theplurality of auxiliary converters 126 includes a hybrid rectifier and anactive rectifier.

Furthermore, the plurality of auxiliary converters 126 is coupled toeach other to form an auxiliary output terminal (not shown). Inaccordance with aspects of the present specification, the main outputterminal of the main converter 124 is coupled to the auxiliary outputterminal in series to form a common output terminal (not shown).Further, a load (not shown) may be coupled across the main outputterminal and the auxiliary output terminal. For example, the load may becoupled to the common output terminal.

It may be noted that conventional wireless power transfer systems maytypically include a single receiver coil. This receiver coil contributestowards supply of a voltage to a load, such as a battery. In onescenario, if the receiver coil is not aligned with a transmitter coil,in order to induce a desired voltage in the receiver coil, the currentin the transmitter coil has to be higher than the current in thetransmitter coil, when the receiver coil is aligned with the transmittercoil. As a result, efficiency of the conventional wireless powertransfer system is compromised. Shortcomings of the conventionalwireless power transfer systems can be overcome using the examplewireless power transfer system 100.

As noted hereinabove, the example receiver unit 108 includes theauxiliary receiver coils 122 in addition to the main receiver coil 120.The combination of the main receiver coil 120 and the auxiliary receivercoils 122 is configured to provide a desired voltage to the load, viathe main and auxiliary converters 124, 126, even in an event ofmisalignment of the main receiver coil 120 with respect to thetransmitter coil 114.

It may be noted herein that if a central axis of the transmitter coil114 is aligned with a central axis of the main receiver coil 120, themain receiver coil 120 is aligned with the transmitter coil 114. Thecentral axis of the transmitter coil 114 is an axis passing through acenter of the transmitter coil 114. Similarly, the central axis of themain receiver coil 120 is an axis passing through a center of the mainreceiver coil 120.

In one embodiment, when the receiver coil 116 is in alignment with thetransmitter coil 114, the transmitter unit 106 provides power to theload. In particular, during operation of the wireless power transfersystem 100, power provided from the power source 104 is converted fromone form to another form by the transmitter drive subunit 112 andprovided to the transmitter coil 114. More particularly, the lowfrequency or direct current (DC) power fed from the power source 104 isconverted to a high frequency power by the transmitter drive subunit112. Accordingly, the transmitter coil 114 is energized and a magneticfield is generated at the transmitter coil 114. The magnetic field atthe transmitter coil 114 induces voltages at the main receiver coil 120and the plurality of auxiliary receiver coils 122 based on alignment ofthe main receiver coil 120 and the plurality of auxiliary receiver coils122 with respect to the transmitter coil 114.

The combination of voltages induced at the main receiver coil 120 andthe plurality of auxiliary receiver coils 122 may be referred to as afirst voltage. The voltages induced at the main receiver coil 120 andthe plurality of auxiliary receiver coils 122 are transmitted to themain converter 124 and the plurality of auxiliary converters 126,respectively. A rectified voltage is generated at the main outputterminal of the main converter 124 and another rectified voltage isgenerated at the auxiliary output terminal of the plurality of auxiliaryconverters 126. In accordance with aspects of the present specification,a combination of the voltage obtained at the main output terminal andthe voltage obtained at the auxiliary output terminal is provided to theload (not shown). The combination of the voltages obtained at the mainoutput terminal and the voltage obtained at the auxiliary outputterminal may be referred to as a second voltage.

It should be noted herein that if a central axis of the transmitter coil114 is aligned with a central axis of the main receiver coil 120, themain receiver coil 120 is aligned with the transmitter coil 114. Whenthe main receiver coil 120 is aligned with the transmitter coil 114, themain receiver coil 120 has a maximum magnetic coupling with thetransmitter coil 114. In the event of maximum magnetic coupling betweenthe transmitter coil 114 and the main receiver coil 120, a highervoltage is induced across the main receiver coil 120 compared to avoltage induced at the main receiver coil 120 during a misalignedcondition of the main receiver coil 120 with respect to the transmittercoil 114. In such a scenario, the voltage induced across the auxiliaryreceiver coils 122 is a considerably lower value. However, a cumulativevoltage across the main output terminal of the main converter 124 andthe auxiliary output terminal of the auxiliary converters 126 is arelatively higher value, for example, ‘X’ volts.

In another scenario where the main receiver coil 120 is misaligned withrespect to the transmitter coil 114, at least one of the auxiliaryreceiver coils 122 may be in alignment with the transmitter coil 114. Itshould be noted herein that if a central axis of the transmitter coil114 is aligned with a central axis of the auxiliary receiver coil 122,the transmitter coil 114 is aligned with the auxiliary receiver coil122. In such a scenario, a voltage induced at the particular auxiliaryreceiver coil 122, which is in alignment with the transmitter coil 114,is higher than a voltage induced in the other auxiliary coils 122. Hereagain, a cumulative voltage across main terminal of the main converter124 and the auxiliary terminal of the auxiliary converters 126 is ahigher value, for example, ‘Y’ volts, where ‘Y’ volts is approximatelyequal to ‘X’ volts. The cumulative voltage ‘Y’ volts is induced withouta significant increase in a magnitude of the current flowing in thetransmitter coil 114. Thus, even during a misaligned condition of themain receiver coil 120 with respect to the transmitter coil 114, adesired voltage required is provided to the load without a significantincrease in the magnitude of the current flowing in the transmitter coil114. Accordingly, an efficiency of power transfer in the wireless powertransfer system 100 is not compromised even in the event of misalignmentof the main receiver coil 120 with respect to the transmitter coil 114.

Additionally, in conventional wireless power transfer systems,communication between a receiver coil and a transmitter coil is hinderedif the receiver coil is misaligned with respect to the transmitter coil.In accordance with the embodiment of the present specification, use ofthe of the auxiliary receiver coils 122, enhances communication betweenthe receiver unit 108 and the transmitter unit 106 compared to aconventional wireless power transfer system having a receiver unitdevoid of auxiliary receiver coils.

It may be noted that in a typical wireless power transfer system, atransmitter unit is configured to communicate with a receiver unit. Inparticular, the receiver unit sends configuration and control feedbacksignals to the transmitter unit, about a status of the receiver unitsuch that the transmitter unit can determine whether to transmit powerto the receiver unit. In one embodiment, the status of the receiver unitmay be a presence of the receiver unit proximate to the transmitterunit. In conventional wireless power transfer systems, when a receivercoil is misaligned with respect to a transmitter coil, communicationbetween the receiver unit and the transmitter unit is affected andhence, the transmitter unit fails to receive the feedback signals fromthe receiver unit. Lack of communication between the receiver unit andthe transmitter unit causes the transmitter unit to stop supply of powerto the receiver unit. In accordance with the example embodiment of thepresent disclosure, use of auxiliary receiver coils 122 aids incontinuous communication between the receiver unit 108 and thetransmitter unit 106 even when the main receiver coil 120 is in amisaligned condition with respect to the transmitter coil 114. Inaccordance with aspects of the present specification, even if the mainreceiver coil 120 is misaligned with respect to the transmitter coil114, at least one of the auxiliary receiver coils 122 is aligned withthe transmitter coil 114. Hence, the receiver unit 108 continues to sendfeedback signals to the transmitter unit 106. This aids in maintainingcontinuity in communication between the transmitter unit 106 and thereceiver unit 108.

FIG. 1B is a block diagram of another example wireless power transfersystem based on the wireless power transfer system 100 described withregard to FIG. 1A. The wireless power transfer system 100 includes awireless power transfer unit 102 and a power source 104. In theillustrated embodiment, the wireless power transfer unit 102 includes atransmitter unit 106, a receiver unit 108, and a field focusing coil 110as described in FIG. 1A. In the example of FIG. 1B, the receiver unit108 includes an integrated electronic component 117.

Conventionally, switches and other electronics of a receiver unit arediscrete electronic components soldered to a printed circuit board. Useof these discrete electronic components increases footprint of such areceiver unit. As a result, use of the receiver unit in compact devices,like mobile phones, laptops, and the like can be a challenge. Theabove-mentioned drawbacks associated with the conventional receiver unitmay be overcome by use of the example integrated electronic component117. In particular, the integrated electronic component 117 includeselectronics of the receiver unit 108. More particularly, the integratedelectronic component 117 includes the first switches of the receiverdrive subunit 118, the second switch of the communication subunit 130,the demodulator 136, connections between the first switches, connectionsbetween the communication subunit 130 and receiver drive subunit 118,formed on the substrate 132. In a similar manner, any other associatedelectronic switches of the receiver unit 108 may be formed on thesubstrate 132. In one embodiment, the substrate may be a thin siliconwafer. Further, the controller 128 is disposed on the substrate 132.Furthermore, the substrate 132 is packaged in a package unit 134 toprovide externally extending connection pins.

The integrated electronic component 117 has a substantially lowerfootprint, thereby facilitating easy incorporation of the integratedelectronic component 117 into compact devices such as the mobile phone,for example. Moreover, use of the integrated electronic component 117facilitates to reduce effects of circuit parasitics, such as trackimpedance and associated voltage drop. Furthermore, use of theintegrated electronic component 117 facilitates to enhance misalignmenttolerance compared to use a conventional receiver drive subunit havingdiscrete electronic components.

The integrated electronic component 117 is an integrated circuit (IC).In one embodiment, the integrated electronic component 117 may be anapplication specific integrated circuit (ASIC), a very large-scaleintegration (VLSI) chip, a microelectromechanical system (MEMS), orsystem on chip (SoC). The integrated electronic component 117 alsoincludes a receiver drive subunit 118, a controller 128, a communicationsubunit 130, and a substrate 132. The controller 128, the communicationsubunit 130, and the receiver drive subunit 118 are disposed/formed onthe substrate 132. In one embodiment, the substrate 132 may include asilicon wafer.

The controller 128 includes a microcontroller, a microprocessor, aprocessing unit, microcomputer, digital signal processors (DSPs), fieldprogrammable gate arrays (FPGAs), and/or any other programmable circuitsor the like. Further, the controller 128 is operatively coupled to thereceiver drive subunit 118 and the communication subunit 130. Inparticular, the controller 128 is operatively coupled to the commonoutput terminal and alternating current (AC) terminal of the receiverdrive subunit 118. The alternating current terminal of the receiverdrive subunit 118 includes alternating current terminal of the mainconverter 124 and alternating current terminals of the auxiliaryconverters 126. The communication subunit 130 includes at least onesecond switch. The at least one second switch includes semiconductorswitches, such as an insulated gate bipolar transistor, a metal oxidesemiconductor field effect transistor, a field-effect transistor, aninjection enhanced gate transistor, an integrated gate commutatedthyristor, a gallium nitride based switch, a silicon carbide basedswitch, a gallium arsenide based switch, diodes, or the like.

The controller 128 is configured to determine one or more circuitparameters of the receiver drive subunit 118. In particular, thecontroller 128 is configured to determine the one or more circuitparameters of at least one of the common output terminal, an alternatingcurrent terminal of the main converter 124, and alternating currentterminals of the plurality of auxiliary converters 126. The term‘circuit parameters,’ as used herein, may refer to voltage, current,frequency, and power. Further, the controller 128 is configured tocontrol operation of the communication subunit 130 based on thedetermined circuit parameters. In particular, the controlling operationof the communication subunit 130 includes activating/deactivating the atleast one second switch.

It should be noted herein that the controlling operation of thecommunication subunit 130 causes a variation in an impedance of thereceiver unit 108. In particular, the impedance loading the mainreceiver coil 120 and the impedance loading the auxiliary receiver coils122, as seen from the transmitter unit 106 end is varied. As a result ofvariation of the impedance, a current at the transmitter unit 106varies. Accordingly, a communication between the transmitter unit 106and the receiver unit 108 is established.

In another embodiment, the transmitter unit 106 is also configured tocommunicate with the receiver unit 108. Hence, a bidirectionalcommunication between the transmitter unit 106 and the receiver unit 108is desirable. Information is transmitted from the transmitter unit 106to the receiver unit 108 by varying a frequency/amplitude of a voltagesignal at the transmitter unit 106. In one example, the informationtransmitted from the transmitter unit 106 may be representative of powerproviding capability of the transmitter unit 106. In another example,the information transmitted from the transmitter unit 106 may berepresentative of an identification packet for the correspondingtransmitter unit 106. Voltage signals at at least one of the alternatingcurrent terminals of the main converter 124 and plurality of auxiliaryconverters 126 is varied as a result of the variation of thefrequency/amplitude of the voltage signal at the transmitter unit 106.Subsequently, the voltage signal at at least one of the alternatingcurrent terminals of the main converter 124 and plurality of auxiliaryconverters 126 is demodulated by a demodulator 136 of the communicationsubunit 130. Accordingly, the information transmitted from thetransmitter unit 106 is interpreted at the receiver unit 108. Further,the demodulator 136 provides a demodulated signal to the controller 128for subsequent action. In one embodiment, the demodulated signal isobtained by using techniques, such as but not limited to frequencyand/or amplitude demodulation, frequency shift keying demodulation, andamplitude shift keying demodulation.

FIG. 2 is a schematic representation 200 of an example receiver unit108. For example, the receiver unit 108 may be used in the wirelesspower transfer system 100 of FIGS. 1A and 1B. In the illustratedembodiment, the receiver unit 108 is coupled to a load 202. In oneembodiment, the load 202 includes a battery pack or battery charger. Thereceiver unit 108 includes the receiver coil 116 and the integratedelectronic component 117. The receiver coil 116 includes the mainreceiver coil 120 and two auxiliary receiver coils 122 a, 122 b. Themain receiver coil 120 and the auxiliary receiver coils 122 a, 122 b areresonant coils. The main receiver coil 120 is coupled to a capacitorC_(rx1). Further, the auxiliary receiver coil 122 a is coupled to acapacitor C_(a1) and the auxiliary receiver coil 122 b is coupled toanother capacitor C_(a2).

The integrated electronic component 117 includes the substrate 132, thereceiver drive subunit 118, the controller 128, and the communicationsubunit 130. The receiver drive subunit 118 and the communicationsubunit 130 are formed on the substrate. Further, the controller 128 isdisposed on the substrate. Further, the substrate 132 along with thereceiver drive subunit 118, the controller 128, and the communicationsubunit 130 are disposed within a package unit (not shown) to form acompact integrated electronic component 117. In one example, thesubstrate 132 along with the receiver drive subunit 118, the controller128, and the communication subunit 130 are hermetically sealed in thepackage unit.

In the illustrated embodiment, the receiver drive subunit 118 includesthe main converter 124 and a plurality of auxiliary converters 126 a,126 b. The main receiver coil 120 is coupled to the main converter 124.The auxiliary receiver coil 122 a is coupled to the auxiliary converter126 a and the other auxiliary receiver coil 122 b is coupled to theauxiliary converter 126 b. Further, an alternative switch 204 such as adiode is coupled across the auxiliary converters 126 a, 126 b. Thealternative switch 204 may also be referred to as a third switch.

The main converter 124 includes the first switches 206. Further, theauxiliary converters 126 a, 126 b includes the first switches 208. Inthe illustrated embodiment, the first switches 206, 208 include a diode.In another embodiment, the first switches 206, 208 may includesemiconductor switches such as an insulated gate bipolar transistor, ametal oxide semiconductor field effect transistor, a field-effecttransistor, an injection enhanced gate transistor, an integrated gatecommutated thyristor, a gallium nitride based switch, a silicon carbidebased switch, a gallium arsenide based switch, or the like. Further, themain converter 124 and auxiliary converters 126 a, 126 b include apassive rectifier. In another embodiment, the main converter 124 andauxiliary converters 126 a, 126 b may include a hybrid rectifier and anactive rectifier. The term ‘hybrid rectifier,’ as used herein, refers toa rectifier circuit having a combination of passive switches and activeswitches.

The main converter 124 includes the main output terminal 210. Theauxiliary converter 126 a is coupled in parallel to the auxiliaryconverter 126 b to form an auxiliary output terminal 212. Further, themain output terminal 210 is coupled in series to the auxiliary outputterminal 212 to form a common output terminal 214. Furthermore, the load202 is coupled across the common output terminal 214.

Further, the main converter 124 includes an alternating current terminal216 having two branches 216 a, 216 b. The auxiliary converter 126 aincludes an alternating current terminal 218 and the auxiliary converter126 b includes an alternating current terminal 220. The alternatingcurrent terminal 218 includes two branches 218 a, 218 b. Further, thealternating current terminal 220 include two branches 220 a, 220 b.

Further, the receiver unit 108 includes an output enable switch 228formed on the substrate 132. Further, the receiver unit 108 includescapacitors C₁ and C_(dc) coupled to the output enable switch 228. Thecapacitor C₁ is coupled in parallel to the common output terminal 214.Furthermore, the load 202 is coupled parallel to the capacitor C_(dc).It should be noted herein that the capacitors C₁ and C_(dc) and the load202 do not form a part of the integrated electronic component 117.

Additionally, the receiver unit 108 includes a plurality of impedancecomponents 230. For the ease of representation, the plurality ofimpedance components 230 are also represented as Z₁, Z₂, Z₃, Z₄, Z₅, andZ₆. The plurality of impedance components 230 are disposed external tothe integrated electronic component 117.

The communication subunit 130 includes a plurality of second switches222 coupled to each other. For ease of representation, the plurality ofsecond switches 222 is also represented as S₁, S₂, S₃, S₄, S₅, and S₆.The plurality of second switches 222 includes semiconductor switchessuch as an insulated gate bipolar transistor, a metal oxidesemiconductor field effect transistor, a field-effect transistor, aninjection enhanced gate transistor, an integrated gate commutatedthyristor, a gallium nitride based switch, a silicon carbide basedswitch, a gallium arsenide based switch, a diode, or the like.

Further, the communication subunit 130 is coupled to the alternatingcurrent terminals 216, 218, 220. In particular, the second switches 222are coupled to the alternating current terminals 216, 218, 220 via theimpedance components 230. More particularly, the switch S₁ is coupled tothe branch 216 a via the impedance component Z₁ and the switch S₂ iscoupled to the branch 216 b via the impedance component Z₂. Further, theswitch S₃ is coupled to the branch 218 a via the impedance component Z₃and the switch S₄ is coupled to the branch 218 b via the impedancecomponent Z₄. Furthermore, the switch S₅ is coupled to the branch 220 avia the impedance component Z₅ and the switch S₆ is coupled to thebranch 220 b via the impedance component Z₆.

The controller 128 is coupled to a current sensor 224 and a voltagesensor 226. In particular, the controller 128 is configured to determinecircuit parameters such as value of current and voltage at the commonoutput terminal 214. More particularly, the controller 128 is configuredto receive the values of current at the common output terminal 214measured by the current sensor 224. In another embodiment, the currentsensor 224 can be located after the capacitor C₁ in series with theswitch 228. Further, the controller 128 is configured to receive thevalue of voltage at the common output terminal 214 measured by thevoltage sensor 226. Further, the controller 128 is configured toactivate and/or deactivate the output enable switch 228. Furthermore,the controller 128 is configured to activate and/or deactivate thesecond switches 222 of the communication subunit 130 based on thedetermined circuit parameters.

A method of manufacturing the integrated electronic component 117involves a first step of designing an electric circuit to be formed onthe substrate 132. In the illustrated example of FIG. 2, the electricalcircuit includes first switches 206, 208, connections between the firstswitches 206, 208, the second switches 222, connections between thesecond switches 222, connections between the first switches 206, 208 andthe second switches 222, the output enable switch 228, the alternativeswitch 204, connection of the alternative switch 204 to the auxiliaryoutput terminal 212, the connection of the output enable switch 228 tothe common output terminal 214, and the demodulator 136.

At a second step, a circuit layout of the electrical circuit that needsto be disposed on the substrate 132 is designed using different toolssuch as Verilog, MATLAB, Simulink, VHDL, and the like. The circuitlayout includes different patterns corresponding to different processlayers such as a N+ diffusion layer, a P+ diffusion layer, a metallayer, a N-well layer, a contact cut layer, a polysilicon layer, and thelike.

At a third step, a mask is manufactured for each of the process layers.For example, one mask may correspond to the N+ diffusion layer andanother mask may correspond to the contact cut layer. In a similarmanner, masks for other process layers are manufactured. It should benoted herein that a mask is formed by etching the pattern of eachprocess layer on a corresponding glass sheet. A plurality of such maskscorresponding to the process layers is produced.

Further, at a fourth step, each mask is used to develop a correspondingpattern on the substrate 132 using a photolithography technique to forma corresponding process layer. Accordingly, the process layers aredeveloped on the substrate 132 to form the electrical circuit.

At a fifth step, the controller 128 is disposed on the substrate 132 ata designated location to establish connection to the second switches222, the output enable switch 228, and the common output terminal 214.Subsequently, at a sixth step, the substrate 132 is disposed in thepackage unit 134 to provide exteriorly extending connection pins.

During operation of the wireless power transfer system 100, during aninitial state, such as at a time instant t=0, the main receiver coil 120or the auxiliary receiver coils 122 a, 122 b are powered by thetransmitter coil 114. Further, at time t=0, the transmitter unit 106 maybe configured to send ping signals to the receiver unit 108. In oneembodiment, the ping signals may be a variation in power at thetransmitter unit 106 which may cause a variation of the circuitparameters at the receiver unit 108. These circuit parameters mayinclude the voltage, current, or power (or any combination thereof) atthe common output terminal 214, in one example. Also, at the timeinstant t=0, the output enable switch 228 may be in a deactivated state.

Subsequently, for example, at a time instant t=t₁, the receiver unit 108acknowledges the ping signal sent from the transmitter unit 106. Inparticular, the receiver unit 108 may be configured to send aninformation having one or more bit patterns, such as a 11-bit pattern.In one embodiment, the bit patterns may be representative of the signalstrength received by the receiver unit 108 and/or an identificationinformation of the receiver unit 108. The ping signal sent from thetransmitter unit 106 and the acknowledgement sent by the receiver unit108 is indicative of the communication between the receiver unit 108 andthe transmitter unit 106. Further, at the time instant t=t₂, wheret₂>t₁, the output enable switch 228 may be activated. The output enableswitch 228 may be activated by providing a gate control signal to theoutput enable switch 228 by the controller 128.

Moreover, to enable communication between the transmitter unit 106 andthe receiver unit 108, the controller 128 controls switching of theswitches S₁ and S₂ based on the measurement of circuit parameters at thecommon output terminal 214. In particular, the controller 128 isconfigured to activate and/or deactivate the switches S₁ and S₂ byproviding the corresponding gate control signal to the switches S₁ andS₂. In one embodiment, when the switch S₁ is activated, the switch S₂ isalso activated. The impedance loading the main receiver coil 120, asseen by the transmitter unit 106 end varies based on activation and/ordeactivation of the switches S₁ and S₂. As a result, the value ofcurrent at the transmitter unit 106 is varied. The variation of currentat the transmitter unit 106 is in the form of the bit pattern isconfigured to provide information to the transmitter unit 106.

Information is representative of performance parameters of the receiverunit 108, in one example. This information is transmitted by thereceiver unit 108 to the transmitter unit 106 at regular intervals. Inparticular, information representative of the type of connected load, anamount of power, voltage, or current demanded by the load 202, controlerror, such as, a output voltage error are transmitted by the receiverunit 108. Accordingly, a controller at the transmitter unit 106 may beconfigured to regulate the power provided from the transmitter unit 106to meet any demand of the load.

Furthermore, the switches S₁ to S₆ are switched synchronously. In oneembodiment, the controller 128 controls switching of the switches S₃ andS₄ based on the measurement of circuit parameters at the common outputterminal 214. The impedance loading the auxiliary receiver coil 122 a,as seen from the transmitter unit 106 end is varied based on theswitching of the switches S₃ and S₄. As a result, the value of currentat the transmitter unit 106 is varied. The variation of current at thetransmitter unit 106 is in a form of a bit pattern such as a 11-bitpattern configured to provide information to the transmitter unit 106. Acontroller of the transmitter unit 106 may be configured to regulatepower provided from the transmitter unit 106 to meet a demand of theload 202. The combination of switches S₁, S₂, S₃, S₄, S₅, and S₆ whichare coupled to the main receiver coil 120 and the auxiliary receivercoils 122 a, 122 b, facilitates to enhance communication between thereceiver unit 108 and the transmitter unit 106 compared to an embodimenthaving only the switches S₁ and S₂.

In one embodiment, when the main receiver coil 120 is aligned with thetransmitter coil 114, the auxiliary converters 126 a, 126 b maycontribute a low value of voltage to the load 202. In such anembodiment, the alternative switch 204 provides a path for a flow ofcurrent to prevent flow of current through the auxiliary converters 126a, 126 b. Accordingly, losses in the auxiliary converters 126 a, 126 bis avoided.

In certain other embodiments, if the transmitter unit 106 is supplyingpower but instead of the receiver coils 120, 122 a, 122 b a foreignobject is in the vicinity of the transmitter unit 106, the foreignobject may not communicate with the transmitter unit 106. Accordingly,the transmitter unit 106 does not provide power and thereby preventslocalized heating at the location of the foreign object. The foreignobject may be any metallic object, in one example.

In yet another embodiment, a foreign object in combination with at leastone of the receiver coils 120, 122 a, 122 b may be drawing power fromthe transmitter unit 106. In such an embodiment, the presence of theforeign object is detected by comparing a value of power received at thereceiver coils 120, 122 a, or 122 b with a value of power transmittedfrom the transmitter unit 106. If the difference between the value ofthe power transmitted from the transmitter unit 106 and the value ofpower received at the receiver coils 120, 122 a, or 122 b is higher thana determined threshold value, the presence of the foreign object isdetected. Accordingly, the transmitter unit 106 terminates supply ofpower and thereby prevents localized heating at the location of theforeign object.

Although the embodiment of FIG. 2 shows auxiliary converters 126 a, 126b coupled in parallel to each other, in other embodiments, the auxiliaryconverters 126 a, 126 b may also be coupled to each other in series.Further, although two auxiliary receiver coils 120 a, 120 b andcorresponding auxiliary converters 126 a, 126 b are represented, inother embodiments, a number of auxiliary receiver coils andcorresponding auxiliary converters may vary depending on theapplication.

FIG. 3 is a schematic representation of one embodiment 300 of thereceiver unit 108 of the wireless power transfer system 100. Asdiscussed earlier, the receiver unit 108 is coupled to the load 202. Thereceiver unit 108 includes the receiver coil 116 and the integratedelectronic component 117.

In the illustrated embodiment, the integrated electronic component 117includes the substrate 132, the controller 128, and the communicationsubunit 130. Furthermore, the integrated electronic component 117includes a diode 302 and the output enable switch 228. In the example ofFIG. 3, the communication subunit 130 is operatively coupled to thecommon output terminal 214. In one embodiment, the second switch 222 ofthe communication subunit 130 is operatively coupled to the commonoutput terminal 214 via the corresponding impedance component 230.

As discussed earlier, the controller 128 is configured to measure thecircuit parameters such as voltage, current, and/or power of the commonoutput terminal 214. The controller 128 is configured to controlactivation and/or deactivation of the second switch 222 based on themeasured circuit parameters. Further, the controller 128 is configuredto control activation and/or deactivation of the output enable switch228.

In one embodiment, the integrated electronic component 117 is anintegrated circuit. In one embodiment, the integrated circuit is anapplication specific integrated circuit (ASIC). The integratedelectronic component 117 is packaged in such a manner to provideexternally extending connection pins. In the illustrated embodiment, theconnections pins may be available at locations X₁, X₂, X₃, X₄, X₅, X₆,X₇, X₈, X₉, X₁₀, X₁₁. The external components such as the receiver coils120, 122 a, 122 b, the impedance component 230, and the load 202 may becoupled to the connections pins at the locations X₁, X₂, X₃, X₄, X₅, X₆,X₇, X₈, X₉, X₁₀, X₁₁. Further, the integrated electronic component 117may include additional connection pins for connecting to other externalelectrical, or electronic components (not disclosed herein).

During operation of the wireless power transfer system 100, at the timeinstant time t=0, the receiver unit 108 is powered by the transmitterunit 106. Further, at time t=0, the transmitter unit 106 may beconfigured to send ping signals to the receiver unit 108. The receiverunit 108 acknowledges the ping signals sent from the transmitter unit106. The controller 128 activates the output enable switch 228subsequent to the acknowledgement by the receiver unit 108.

In order to communicate from the receiver unit 108 to the transmitterunit 106, the controller 128 may activate or deactivate the secondswitch 222. When the second switch 222 is activated, the impedancecomponent 230 is connected across the common output terminal 214. As aresult, the impedance loading the receiver coils 120, 122 a, 122 b, asseen by the transmitter unit 106, varies. As a result of variation ofimpedance, a current at the transmitter coil 114 may vary in such amanner that a 11-bit pattern is obtained at the transmitter unit 106.Accordingly, information is transmitted from the receiver unit 108 tothe transmitter unit 106. The information may be representative of thevalue of power or a control error that needs to be provided to the load202. Once the information is received at the transmitter unit 106, thepower, voltage, current, or frequency (or a combination thereof) at thetransmitter unit 106 may be controlled by the controller 128.

As noted hereinabove, when the second switch 222 is activated, theimpedance component 230 is connected across the common output terminal214. If the diode 302 is not present, activation of the second switch222 also provides one closed path via the second switch 222, theimpedance component 230, the output enable switch 228, the capacitorC_(dc), and back to the second switch 222. Further, another closed pathis provided via the second switch 222, the impedance component 230, thecapacitor C₁, and back to the second switch 222. In such a scenario, thecapacitors C₁ and C_(dc) may discharge via the corresponding closedpaths.

The capacitor C_(dc) is a load capacitor. The discharge of the capacitorC_(dc) results in loss of stored energy at a load terminal. In oneexample, the load terminal includes input terminals of a charger stageof a battery of a mobile phone. Hence, the discharge of the capacitorC_(dc) needs to be prevented. Further, C₁ is the capacitor across whichthe circuit parameters of the common output terminal 214 are measured bythe controller 128. The discharge of the capacitor C₁ may cause anundesirable variation in the voltage across the capacitor C₁. Thevariation in voltage across the capacitor C₁ may cause inaccuratemeasurement of circuit parameters at the common output terminal. Hence,the discharge of the capacitor C₁ needs to be prevented.

In order to avoid discharge of the capacitors C₁ and C_(dc), the diode302 is employed. The use of the diode 302 blocks the flow of currentfrom the capacitors C₁ and C_(dc). As a result, the discharge of thecapacitors C₁ and C_(dc) is prevented.

FIG. 4 is a schematic representation of another embodiment 400 of thereceiver unit 108. As discussed earlier, the receiver unit 108 iscoupled to the load 202. The receiver unit 108 includes the mainreceiver coil 120, the auxiliary receiver coils 122 a, 122 b, and theintegrated electronic component 117. The integrated electronic component117 includes the substrate 132, the main converter 124, the auxiliaryconverters 126 a, 126 b, the controller 128, the communication subunit130, and the output enable switch 228.

The communication subunit 130 includes switches 404, 408, and a NOTlogical gate 406. The switch 404 may be alternatively referred to as asecond switch. A gate signal is provided to a gate terminal of theswitch 404. This gate signal is inverted using the NOT logical gate 406and an inverted gate signal is provided to a gate terminal of the switch408. The activation/deactivation of the switches 404, 408 is determinedbased on the gate signals at the gate terminals of the switches 404,408. In one embodiment, when the gate signals corresponding to theswitches 404, 408 are high, the switches 404, 408 are configured to beactivated. In another embodiment, when the gate signals corresponding tothe switches 404, 408 are low, the switches 404, 408 are configured tobe deactivated.

The receiver unit 108 further includes an impedance component 402. Theimpedance component 402 is disposed externally to the integratedelectronic component 117. Further, the receiver unit 108 includes acapacitor C₁ coupled across the common output terminal 214. Furthermore,the capacitor C_(dc) is coupled across the load 202. The output enableswitch 228 is coupled to the capacitors C₁ and C_(dc). The capacitors C₁and C_(dc) are also disposed externally to the integrated electroniccomponent 117.

During operation of the receiver unit 108, at least one of the auxiliaryreceiver coils 122 a, 122 b or main receiver coil 120 is powered by thetransmitter coil 114. Subsequently, the output enable switch 228 isactivated based on the communication between the transmitter unit 106and the receiver unit 108. Further, the controller 128 measures thecircuit parameters at the common output terminal 214. Furthermore, thecontroller 128 controls operation of the communication subunit 130 basedon the measured circuit parameters. In particular, the controller 128controls operations of the switch 404 based on the measured circuitparameters. Accordingly, the switch 404 is activated and/or deactivated.When the switch 404 is activated, the impedance component 402 is coupledacross the common output terminal 214. Accordingly, the impedanceloading the receiver coils 120, 122 a, 122 b as seen from thetransmitter unit 106 end changes. The change in impedance is reflectedas a change in current at the transmitter unit 106.

As a result of activation and/or deactivation of the switch 404, thecurrent at the transmitter coil 114 is varied in such a manner that abit pattern is obtained at the transmitter unit 106. Accordingly, theinformation is transmitted from the receiver unit 108 to the transmitterunit 106.

It may be noted that if both the switches 404 and 408 are activated atsame period of time, a closed path is formed via the switch 404, theimpedance component 402, the switch 408, the output enable switch 228,the capacitor C_(dc), and back to the switch 404. As a result, thecapacitor C_(dc) may discharge via the switch 408, the impedancecomponent 402, and the switch 404. In a similar manner, the capacitor C₁may be discharged. In order to avoid discharge of the capacitors C₁ andC_(dc), the switch 408 has to be deactivated. According to aspects ofthe present specification, when the switch 404 is activated, the switch408 is deactivated. The gate signal provided at the gate terminal of theswitch 404 is inverted by the NOT logic gate 406 and provided to thegate terminal of the switch 408. Accordingly, the switch 408 isdeactivated. As a result of deactivation of the switch 408, thecapacitors C₁ and C_(dc) are disconnected from the common outputterminal 214, thereby preventing discharge of the capacitors C₁ andC_(dc).

Further, the controller 128 measures circuit parameters at thealternating current terminal 216 of the main converter 124 and thealternating current terminals 218, 220 of the auxiliary converters 126a, 126 b respectively. The controller 128 further determines pattern ofswitching of first switches 410 of the main converter 124 based oncircuit parameters at the alternating current terminal 216 of the mainconverter 124. Further, the controller 128 determines the pattern ofswitching of first switches 412 of the auxiliary converters 126 a, 126 bbased on the circuit parameters corresponding to the alternating currentterminals 218, 220 of the auxiliary converters 126 a, 126 b. The term“pattern of switching,” as used herein, may refer to pattern ofactivating/deactivating the first switches 412. Although the example ofFIG. 4 refers to use of the controller 128 to switch the first switches410, 412, use of a separate controller for switching the first switches410, 412 is also envisioned.

FIG. 5 is a detailed circuit representation of a wireless power transfersystem 500 in accordance with one embodiment of the presentspecification. The wireless power transfer system 100 includes the powersource 104, the transmitter unit 106, the receiver unit 108, and a load508. The power source 104 is coupled to the transmitter unit 106. Thetransmitter unit 106 is magnetically coupled to the receiver unit 108.Further, the receiver unit 108 is electrically coupled to the load 508.

The receiver unit 108 includes the receiver drive subunit 118 and thereceiver coil 116. The receiver coil 116 includes the main receiver coil120 and the plurality of auxiliary receiver coils 122. The plurality ofauxiliary receiver coils 122 is represented as A₁, A₂, A₃, and A₄.

The receiver drive subunit 118 includes the main converter 124 and theplurality of auxiliary converters 502. The plurality of auxiliaryconverters 502 are represented as R₁, R₂, R₃, and R₄. In one embodiment,the main converter 124 and the plurality of auxiliary converters 502 arepassive rectifiers. In particular, the main converter 124 and theplurality of auxiliary converters 502 are full bridge passive dioderectifiers. The main converter 124 includes a main output terminal 504.The plurality of auxiliary converters 502 is coupled to each other toform an auxiliary output terminal 506. In the illustrated embodiment,the plurality of auxiliary converters 502 is coupled to each other inparallel. The main converter 124 is coupled in series with the pluralityof auxiliary converters 502. In particular, the main output terminal 504is coupled in series with the auxiliary output terminal 506. Further,the load 508 is coupled across the main output terminal 504 and theauxiliary output terminal 506.

In particular, the power source 104 is coupled to the transmitter drivesubunit 112. In one embodiment, the power source 104 is a direct current(DC) power source. During operation, the DC power provided by the powersource 104 is converted to an alternating current (AC) power by thetransmitter drive subunit 112. As a result, current flows through thetransmitter coil 114 and a magnetic field is generated. Hence, thetransmitter coil 114 is magnetically coupled to the receiver coil 116.

A voltage is induced across the receiver coil 116 due to the magneticcoupling between the transmitter coil 114 and the receiver coil 116.Specifically, a voltage is induced across the main receiver coil 120 andthe auxiliary receiver coils 122 based on alignment with the transmittercoil 114. The voltage induced across the main receiver coil 120 and theauxiliary receiver coils 122 may be alternately referred to as the firstvoltage. For ease of representation, the first voltage induced acrossthe main receiver coil 120 is represented as V_(rx) and the firstvoltage induced across the plurality of auxiliary coils A₁, A₂, A₃, andA₄ are represented as V₁, V₂, V₃, and V₄, respectively. Further, thefirst voltage induced at the main receiver coil 120 is rectified and anoutput voltage V_(a) is obtained at the main output terminal 504. Theoutput voltage V_(a) obtained at the main output terminal 504 is alsoreferred to as a second voltage. The first voltages induced at theauxiliary receiver coils 122 are rectified and an output voltage V_(b)is obtained at the auxiliary output terminal 506. The output voltageV_(b) obtained at the auxiliary output terminal 506 is also referred toas a third voltage. Further, a combination of the second and thirdvoltages V_(a) and V_(b) is provided to the load 508. In one embodiment,the sum of the voltages V_(a) and V_(b) is provided to the load 508.

In an embodiment, when the main receiver coil 120 is aligned with thetransmitter coil 114, the main receiver coil 120 has maximum magneticcoupling with the transmitter coil 114 compared to auxiliary receivercoils 122 (as depicted in FIG. 9A). Hence, the voltage V_(rx) is greaterthan voltages V₁, V₂, V₃, or V₄. In one embodiment, the voltages V₁, V₂,V₃, and V₄ have a negligible value. The voltage V_(rx) is rectified bythe main converter 124 and a voltage V_(a) is generated at the mainoutput terminal 504. Further, at least one of the voltages V₁, V₂, V₃,and V₄ is rectified and a voltage V_(b) is obtained at the auxiliaryoutput terminal 506. Since the voltages V₁, V₂, V₃, and V₄ have anegligible value, the voltage V_(b) has a lower value. The value ofvoltage V_(b) is lesser than the value of voltage V_(a). A combinationof the voltages V_(a) and V_(b) is provided to the load 508. Thus, adesired voltage is provided to the load 508.

In another embodiment, the auxiliary receiver coil A₃ is aligned withthe transmitter coil 114 and the main receiver coil 120 is not inalignment with the transmitter coil 114 (as depicted in FIG. 9B). Inthis scenario, the other auxiliary coils A₁, A₂, and A₄ are also not inalignment with the transmitter coil 114. The auxiliary receiver coil A₃has a maximum magnetic coupling with the transmitter coil 114. Thus, thevoltage induced across the auxiliary receiver coil A₃ is higher than thevoltage induced across other auxiliary receiver coils A₁, A₂, and A₄. Inparticular, the voltage V₃ is greater than voltages V₁, V₂, or V₄.

Furthermore, the auxiliary converters R₁, R₂, R₃, and R₄ are configuredto rectify the voltages induced across auxiliary receiver coils A₁, A₂,A₃, and A₄, respectively. If the auxiliary converters R₁, R₂, R₃, and R₄are coupled in parallel, the voltages at the output of each auxiliaryconverter aid in determination of activation and/or deactivation ofdiodes of the auxiliary converters R₁, R₂, R₃, and R₄. Specifically, thevoltages at the output of each auxiliary converter enable to determinewhich converter among the auxiliary converters R₁, R₂, R₃, and R₄ isoperational. In one example, when the voltage V₃ is greater thanvoltages V₁, V₂, or V₄, the voltage at the output of the auxiliaryconverter R₃ is greater than the voltages at the outputs of theauxiliary converters R₁, R₂, and R₄. If the voltage at the output of theauxiliary converter R₃ is greater than the voltage at the output of theauxiliary converters R₁, R₂, and R₄, the voltage at the output of theauxiliary converter R₃ reverse biases the diodes of the auxiliaryconverters R₁, R₂, and R₄. Therefore, the auxiliary converters R₁, R₂,and R₄ are in a deactivated state and do not contribute towardsrectification of the voltages V₁, V₂, and V₄, respectively. Hence, thecurrent flowing through the auxiliary receiver coils A₁, A₂, and A₄ iszero, thereby preventing power losses. In this scenario, only theauxiliary converter R₃ is operational and the voltage V_(b) obtained atthe auxiliary output terminal 506 is equal to the voltage rectified bythe auxiliary converter R₃. Specifically, in this example, voltage V₃ isrectified by auxiliary converter R₃ to obtain the voltage V_(b) at theauxiliary output terminal 506.

In accordance with aspects of the present specification, the activationand deactivation of the diodes of the auxiliary converters R₁, R₂, R₃,and R₄ are performed without use of controllers. Specifically, theparticular auxiliary converter having the maximum input voltage isactivated and the remaining auxiliary converters are deactivatedresulting in lower power losses.

Although in the illustrated embodiment, each auxiliary receiver coil iscoupled to a corresponding auxiliary converter, in other embodiments, aplurality of auxiliary receiver coils may be coupled to one auxiliaryconverter. Also, although the example of FIG. 5 depicts use of passivediode rectifiers, use of other types of auxiliary converters and mainconverters are envisaged. In one embodiment, the auxiliary convertersand the main converters may be active rectifiers.

FIG. 6 is a detailed circuit representation of a wireless power transfersystem 600 of FIG. 1, in accordance with another embodiment of thepresent specification. The wireless power transfer system 100 includesthe power source 104, the transmitter unit 106, the receiver unit 108,and the load 508. The transmitter unit 106 includes the transmitterdrive subunit 112 coupled to the transmitter coil 114. The receiver unit108 includes the main receiver coil 120, the main converter 124, theplurality of auxiliary receiver coils 122, and the plurality ofauxiliary converters 602. The main receiver coil 120 is coupled to themain converter 124. Further, the plurality of auxiliary receiver coils122 is coupled to the plurality of auxiliary converters 602. Theauxiliary converters 602 are represented as R₁, R₂, R₃, and R₄. Theauxiliary receiver coils 122 are represented as A₁, A₂, A₃, and A₄. Inthe illustrated embodiment, the auxiliary receiver coil A₁ is coupled tothe auxiliary converter R₁, and in a similar manner, the auxiliaryreceiver coils A₂, A₃, and A₄ are coupled to auxiliary converters R₂,R₃, and R₄, respectively.

Further, the auxiliary converter R₁ is coupled in series with auxiliaryconverter R₃. Further, the auxiliary converter R₂ is coupled in serieswith the auxiliary converter R₄. Furthermore, a combination of theauxiliary converters R₁ and R₃ is coupled across the auxiliaryconverters R₂ and R₄ in parallel to form an auxiliary output terminal506. The main converter 124 is coupled in series with the plurality ofauxiliary converters 602, such that the main output terminal 504 of themain converter 124 is in series with the auxiliary output terminal 506.Further, the main converter 124 and the plurality of auxiliaryconverters 602 are coupled across the load 508. Additionally, the mainreceiver coil 120, the main converter 124, the auxiliary receiver coils122, and the auxiliary converters 602 are disposed on a single printedcircuit board 604.

In the presently contemplated configuration, a voltage V_(rx) is inducedacross the main receiver coil 120. The voltage V_(rx) is rectified bythe main converter 124 and the voltage V_(a) is obtained at the mainoutput terminal 504. In a similar manner, voltages V₁, V₂, V₃, and V₄are induced across the auxiliary receiver coils A₁, A₂, A₃, and A₄. Theauxiliary converters R₁, R₃, and R₄ are configured to rectify thevoltages V₁, V₂, V₃, and V₄, respectively.

Rectified voltages at the outputs of the auxiliary converters R₁ and R₃are represented as V_(x) and rectified voltages at the outputs of theauxiliary converters R₂ and R₄ are represented as V_(y). If the voltageV_(x) is greater than the voltage V_(y), diodes of the auxiliaryconverters R₂ and R₄ are reverse biased. In this scenario, the auxiliaryconverters R₂ and R₄ do not rectify the voltages V₂ and V₄ and only theauxiliary converters R₁ and R₃ rectify the voltages V₁ and V₃,respectively. Hence, the current flowing in the auxiliary receiver coilsA₂ and A₄ is zero.

Further, an output voltage V_(b) is obtained at the auxiliary outputterminal 506. In one example, the rectified voltage V_(b) is equal tothe voltage V_(x). A combination of the voltage V_(a) at the main outputterminal 504 and the voltage V_(b) at the auxiliary output terminal 506is provided to the load 508. In one embodiment, a sum of voltages V_(a)and V_(b) may be provided to the load 508.

FIG. 7 is a detailed circuit representation of a wireless power transfersystem 700 in accordance with yet another embodiment of the presentspecification. The wireless power transfer system 100 includes the powersource 104, the transmitter unit 106, the receiver unit 108, and theload 508. The transmitter unit 106 includes the transmitter drivesubunit 112 coupled to the transmitter coil 114. The receiver unit 108includes the main receiver coil 120, the main converter 124, theplurality of auxiliary receiver coils 122, and the plurality ofauxiliary converters 702. The main receiver coil 120 is coupled to themain converter 124. The plurality of auxiliary receiver coils 122 iscoupled to the plurality of auxiliary converters 702. For ease ofrepresentation, the plurality of auxiliary converters 702 arerepresented as HR₁, HR₂, HR₃, and HR₄.

In the example of FIG. 7, each of the main converter 124 and theplurality of auxiliary converters 702 is a center tapped full-wave dioderectifier. The main converter 124 includes two diodes and a center tapterminal 704 which is a contact at a point of the main receiver coil120, preferably at the mid-point of the main receiver coil 120.Similarly, each of the plurality of auxiliary converters 702 includestwo diodes and a center-tap terminal 706 which is a contact at a pointof the corresponding auxiliary receiver coil 122. The two diodes of eachof the converters 124 and 702 are connected to the opposite ends of thecorresponding coils 120, 122.

In accordance with the illustrated embodiments of FIGS. 5-7, the numberof diodes in the plurality of auxiliary converters 702 is half thenumber of diodes in the plurality of auxiliary converters 502 or 602.Power losses are reduced since the plurality of auxiliary converters 702have reduced number of diodes.

As noted hereinabove, a voltage is induced across the main receiver coil120 and the plurality of auxiliary receiver coils 122 based on alignmentwith the transmitter coil 114. The voltage induced across the mainreceiver coil 120 is represented as V_(rx). The main converter 124rectifies the voltage V_(rx) and a voltage V_(a) is obtained at the mainoutput terminal 504. In a similar manner, the auxiliary converters HR₁,HR₂, HR₃, and HR₄ rectify the voltage induced at the auxiliary receivercoils 122. Accordingly, a rectified voltage V_(b) is generated at theauxiliary output terminal 506. Further, a combination of voltages V_(a)and V_(b) is provided to the load 508.

FIG. 8 is a schematic representation of a wireless power transfer unit800 in accordance with one embodiment of the present specification. Thewireless power transfer unit 800 includes the transmitter unit 106 andthe receiver unit 108. In the illustrated embodiment, the transmitterunit 106 has the plurality of transmitter coils 114. The receiver unit108 is disposed in a mobile phone 802. The receiver unit 108 includesthe receiver coil 116 having the main receiver coil 120 and theplurality of auxiliary receiver coils 122. The plurality of auxiliaryreceiver coils 122 is disposed about the central axis 808 of the mainreceiver coil 120. Specifically, the plurality of auxiliary receivercoils 122 disposed on the main receiver coil 120. The main receiver coil120 and the plurality of auxiliary receiver coils 122 are coupled to theload (not shown) via the corresponding converters (not shown). In oneembodiment, the load is a battery or a battery charger of the mobilephone 802.

A voltage is induced across the main receiver coil 120 and the pluralityof auxiliary receiver coils 122 based on the alignment of the mainreceiver coil 120 and the plurality of auxiliary receiver coils 122 withrespect to the transmitter coil 114. Further, the voltage induced at thereceiver coil 116, is rectified and provided to the load. In particular,the voltages at the main receiver coil 120 and the plurality ofauxiliary receiver coils 122 are rectified by the main converter (notshown) and the plurality of auxiliary converters (not shown),respectively. Further, the rectified voltages obtained at the mainoutput terminal (not shown) and the auxiliary output terminal (notshown) is provided to the load, such as the battery. Accordingly, thebattery of the receiver unit 108 is charged.

FIGS. 9A and 9B are cross-sectional representations 900A, 900B of aportion of a wireless power transfer unit 102 in accordance with aspectsof the present specification. In particular, FIGS. 9A and 9B arecross-sectional representations of the transmitter unit 106 and thereceiver unit 108 of the wireless power transfer unit 102. Moreparticularly, FIGS. 9A and 9B depict the transmitter coil 114 and thereceiver coil 116. The orientation of the wireless power transfer unit102 is for illustrative purpose and should not be construed aslimitation of the embodiment.

In particular, in the embodiment of FIG. 9A, the transmitter coil 114 isdisposed on a corresponding ferrite layer 902. Reference numeral 904 isrepresentative of a central axis of the transmitter coil 114. Thecentral axis 904 of the transmitter coil 114 passes through a center ofthe transmitter coil 114 and is in perpendicular to a x-y plane of thetransmitter coil 114. The receiver coil 116 includes the main receivercoil 120 and the auxiliary receiver coils 122. An interface layer 906 isdisposed between the receiver coil 116 and the transmitter coil 114. Theinterface layer 906 may be made of a non-magnetic insulation material,such as Teflon™, any polymer, plastic, ceramic, mylar, and the like.

Further, the main receiver coil 120 is disposed on a correspondingferrite layer 910. The auxiliary receiver coils 122 are disposed aboutthe central axis 808 on the main receiver coil 120. In the illustratedembodiment, the auxiliary receiver coils 122 are disposed between themain receiver coil 120 and the interface layer 906.

Furthermore, the central axis 904 is aligned with the central axis 808.Accordingly, the main receiver coil 120 is aligned with the transmittercoil 114. When the main receiver coil 120 is aligned with thetransmitter coil 114, the main receiver coil 120 has maximum magneticcoupling with the transmitter coil 114 compared to the auxiliaryreceiver coils 122. Hence, a higher voltage is induced across the mainreceiver coil 120 compared to a voltage induced across the auxiliaryreceiver coils 122. Although the embodiment of FIG. 9A represents thetransmitter coil 114 aligned with the main receiver coil 120, in anotherembodiment, the main receiver coil 120 may be misaligned with respect tothe transmitter coil 114 and at least one of the auxiliary receivercoils 122 may be aligned with respect to the transmitter coil 114.

Referring now to FIG. 9B, the transmitter coil 114 is disposed on theferrite layer 902. The auxiliary receiver coils 122 are disposed on acorresponding ferrite layer 910. Further, the main receiver coil 120 isdisposed on the auxiliary receiver coils 122 such that the auxiliaryreceiver coils 122 are sandwiched between the ferrite layer 910 and themain receiver coil 120. The main receiver coil 120 is disposed betweenthe auxiliary receiver coils 122 and the interface layer 906.

In the illustrated embodiment, the central axis 808 of the main receivercoil 120 is misaligned with respect to the central axis 904 of thetransmitter coil 114. The misalignment of the central axis 808 withrespect to the central axis 904 is represented by reference numeral 908.In this embodiment, the auxiliary receiver coil A₃ is aligned withrespect to the transmitter coil 114. Accordingly, the auxiliary receivercoil A₃ has a maximum magnetic coupling with the transmitter coil 114compared to the main receiver coil 120 and the auxiliary receiver coilA₂ with the transmitter coil 114. Thus, a voltage induced across theauxiliary receiver coil A₃ is higher than a voltage induced across theauxiliary receiver coil A₂. Further, in this embodiment, a voltageinduced across the main receiver coil 120 is lower compared to a voltageinduced across the auxiliary receiver coil A₃, which is aligned withrespect to the transmitter coil 114. However, a combination of a voltageinduced at the auxiliary receiver coil A₃ and a voltage induced at themain receiver coil 120 is provided to the corresponding converters forrectification and subsequently, to a load (not shown). Thus, a desiredvoltage is provided to the load irrespective of aligned or misalignedconditions of the main receiver coil 120 with respect to the transmittercoil 114. It may be noted that in this scenario, the current in thetransmitter coil 114 does not increase substantially. As a result,transfer of desired power to the load is achieved.

Although the illustrated embodiment of FIG. 9B represents thetransmitter coil 114 misaligned with respect to the main receiver coil120, in another embodiment, the main receiver coil 120 may be alignedwith respect to the transmitter coil 114 and the auxiliary receivercoils 122 may be misaligned with respect to the transmitter coil 114.

FIG. 10A is a schematic representation of the receiver coil 120 of thewireless power transfer system in accordance with an embodiment of thepresent specification. In particular, FIG. 10B is a top view of thereceiver coil 116. The receiver coil 116 includes the main receiver coil120 and plurality of auxiliary receiver coils 122 a, 122 b, 122 c, 122d.

Reference numeral 808 is representative of a central axis of the mainreceiver coil 120. The central axis 808 is referred to as an axispassing through a center and perpendicular to a x-y plane of the mainreceiver coil 120.

In the illustrated embodiment, the main receiver coil 120 is disposeddirectly on a ferrite layer 910. According to aspects of the presentspecification, the plurality of auxiliary receiver coils 122 a, 122 b,122 c, 122 d is disposed about the central axis 808. In the illustratedembodiment, four auxiliary receiver coils 122 are disposed about themain receiver coil 120. The number of auxiliary receiver coils may varydepending on the application.

Referring to FIG. 10B, a schematic representation of a receiver coil 116in accordance with an embodiment of the present specification ispresented. In particular, FIG. 10B is a top view of the receiver coil116. The receiver coil 116 includes the main receiver coil 120 and theplurality of auxiliary receiver coils 122.

The main receiver coil 120 has a first surface 1002 and a second surface1004. The first surface 1002 is opposite to the second surface 1004.Further, the main receiver coil 120 has a peripheral side 1006, an inneredge 1005, and an outer edge 1007.

In the illustrated embodiment, the main receiver coil 120 is a flatstructure. Specifically, the main receiver coil 120 is square shaped, orrectangular shaped, or oval shaped, or circular shaped, or quadrilateralshaped, or the like. A center portion of the main receiver coil 120 ishollow. The main receiver coil 120 is disposed directly on a ferritelayer 910. Specifically, the second surface 1004 is in direct contactwith the ferrite layer 910. In another embodiment, the first surface1002 may be in direct contact with the ferrite layer 910.

According to aspects of the present specification, the plurality ofauxiliary receiver coils 122 is disposed about the central axis 808. Inthe illustrated embodiment, four auxiliary receiver coils 122 aredisposed on the main receiver coil 120. Specifically, the plurality ofauxiliary receiver coils 122 is disposed on at least one of the firstsurface 1002 and the second surface 1004 of the main receiver coil 120.In another embodiment, the auxiliary receiver coils 122 are disposedpartially on the main receiver coil 120. In yet another embodiment, theauxiliary receiver coils 122 are disposed proximate to the along theouter edge 1007 proximate to the main receiver coil 120. The number ofauxiliary receiver coils 122 may vary depending on the application.

Furthermore, in one embodiment, all the auxiliary receiver coils 122 areequidistant from the central axis 808. In another embodiment, eachauxiliary receiver coil of the plurality of auxiliary receiver coils 122is disposed at a different distance from the central axis 808. In yetanother embodiment, the auxiliary receiver coils 122 are symmetricallydisposed about the central axis 808. In yet another embodiment, theauxiliary receiver coils 122 are unsymmetrically disposed about thecentral axis 808. In yet another embodiment, the plurality of auxiliaryreceiver coils 122 may be arranged concentric to the main receiver coil120. In yet another embodiment, the auxiliary receiver coils 122 are ina different plane with respect to each other and the main receiver coil120. In yet another embodiment, one auxiliary receiver coil 122 overlapsanother auxiliary receiver coil 122.

The auxiliary receiver coils 122 may be square shaped, rectangularshaped, oval shaped, circular shaped, quadrilateral shaped, or the like.The auxiliary receiver coils 122 are symmetrically shaped orunsymmetrically shaped. In the illustrated embodiment, a center portionof each of the auxiliary receiver coils 122 is hollow.

Although the illustrated embodiment shows only four auxiliary receivercoils 122 disposed on the main receiver coil 120, number of auxiliaryand main receiver coils may vary depending on the application. Further,although the illustrated embodiment shows auxiliary receiver coils 122distributed sparsely about the central axis 808, in one embodiment, theauxiliary receiver coils 122 may be distributed densely about thecentral axis 808.

In accordance with the embodiments discussed herein, the arrangement ofthe main receiver coil and the plurality of auxiliary receiver coilsaids in enhancing communication with the transmitter coil and allowsefficient power transfer between the transmitter coil and the receivercoils even in the event of misalignment of the main receiver coil withthe transmitter coil. Further, the arrangement of the auxiliaryconverters aids in activation and deactivation of the diodes of theauxiliary converters without use of controllers. Furthermore, thewireless power transfer system adjusts misalignments between thetransmitter unit and the receiver unit without employing sensors or anyother detection techniques, such as camera.

In accordance with the embodiments discussed herein, the arrangement ofthe main receiver coil, the plurality of auxiliary receiver coils, andthe corresponding converters facilitate efficient power transfer betweenthe transmitter coil and the receiver coils even in the event of amisalignment of the main receiver coil with respect to the transmittercoil. Further, the main converter, the auxiliary converters, and otherrelated electronics of the receiver unit are formed on a substrate toform an integrated electronic component. Accordingly, the footprint ofthe corresponding electronics of the receiver unit is considerablyreduced.

FIGS. 1-10B and the operations described herein are examples meant toaid in understanding example implementations and should not be used tolimit the potential implementations or limit the scope of the claims.Some implementations may perform additional operations, feweroperations, operations in parallel or in a different order, and someoperations differently.

Unless defined otherwise, technical and scientific terms used hereinhave the same meaning as is commonly understood by one of ordinary skillin the art to which this specification belongs. The terms “first”,“second”, and the like, as used herein do not denote any order,quantity, or importance, but rather are used to distinguish one elementfrom another. Also, the terms “a” and “an” do not denote a limitation ofquantity, but rather denote the presence of at least one of thereferenced items. The use of “including,” “comprising” or “having” andvariations thereof herein are meant to encompass the items listedthereafter and equivalents thereof as well as additional items. Theterms “connected” and “coupled” are not restricted to physical ormechanical connections or couplings, and can include electricalconnections or couplings, whether direct or indirect. Furthermore, terms“circuit” and “circuitry” and “controlling unit” may include either asingle component or a plurality of components, which are active and/orpassive and are connected or otherwise coupled together to provide thedescribed function. In addition, the term operatively coupled as usedherein includes wired coupling, wireless coupling, electrical coupling,magnetic coupling, radio communication, software based communication, orcombinations thereof.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

The various illustrative logics, logical blocks, modules, circuits andalgorithm processes described in connection with the implementationsdisclosed herein may be implemented as electronic hardware, computersoftware, or combinations of both. The interchangeability of hardwareand software has been described generally, in terms of functionality,and illustrated in the various illustrative components, blocks, modules,circuits and processes described throughout. Whether such functionalityis implemented in hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the variousillustrative logics, logical blocks, modules and circuits described inconnection with the aspects disclosed herein may be implemented orperformed with a general purpose single- or multi-chip processor, adigital signal processor (DSP), an application-specific integratedcircuit (ASIC), a field-programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general-purpose processor may be amicroprocessor, or, any conventional processor, controller,microcontroller, or state machine. A processor also may be implementedas a combination of computing devices, e.g., a combination of a DSP anda microprocessor, a plurality of microprocessors, one or moremicroprocessors in conjunction with a DSP core, or any other suchconfiguration. In some implementations, particular processes and methodsmay be performed by circuitry that is specific to a given function.

In one or more aspects, the functions described may be implemented inhardware, digital electronic circuitry, computer software, firmware,including the structures disclosed in this specification and theirstructural equivalents thereof, or in any combination thereof.Implementations of the subject matter described in this specificationalso can be implemented as one or more computer programs, i.e., one ormore modules of computer program instructions, encoded on a computerstorage media for execution by, or to control the operation of, dataprocessing apparatus.

If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. The processes of a method or algorithmdisclosed herein may be implemented in a processor-executable softwaremodule which may reside on a computer-readable medium. Computer-readablemedia includes both computer storage media and communication mediaincluding any medium that can be enabled to transfer a computer programfrom one place to another. A storage media may be any available mediathat may be accessed by a computer. By way of example, and notlimitation, such computer-readable media may include RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that may be used to storedesired program code in the form of instructions or data structures andthat may be accessed by a computer. Also, any connection can be properlytermed a computer-readable medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk, and Blu-ray′ disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations also can be included within the scope of computer-readablemedia. Additionally, the operations of a method or algorithm may resideas one or any combination or set of codes and instructions on a machinereadable medium and computer-readable medium, which may be incorporatedinto a computer program product.

Various modifications to the implementations described in thisdisclosure may be readily apparent to those skilled in the art, and thegeneric principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the claims are not intended to be limited to theimplementations shown herein, but are to be accorded the widest scopeconsistent with this disclosure, the principles and the novel featuresdisclosed herein.

Certain features that are described in this specification in the contextof separate implementations also can be implemented in combination in asingle implementation. Conversely, various features that are describedin the context of a single implementation also can be implemented inmultiple implementations separately or in any suitable subcombination.Moreover, although features may be described as acting in certaincombinations and even initially claimed as such, one or more featuresfrom a claimed combination can in some cases be excised from thecombination, and the claimed combination may be directed to asubcombination or variation of a subcombination.

Similarly, while operations are depicted in the drawings in a particularorder, this should not be understood as requiring that such operationsbe performed in the particular order shown or in sequential order, orthat all illustrated operations be performed, to achieve desirableresults. Further, the drawings may schematically depict one more exampleprocesses in the form of a flow diagram. However, other operations thatare not depicted can be incorporated in the example processes that areschematically illustrated. For example, one or more additionaloperations can be performed before, after, simultaneously, or betweenany of the illustrated operations. In certain circumstances,multitasking and parallel processing may be advantageous. Moreover, theseparation of various system components in the implementations describedshould not be understood as requiring such separation in allimplementations, and it should be understood that the described programcomponents and systems can generally be integrated together in a singlesoftware product or packaged into multiple software products.Additionally, other implementations are within the scope of thefollowing claims. In some cases, the actions recited in the claims canbe performed in a different order and still achieve desirable results.

While the disclosure has been described with reference to exampleembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the disclosure. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the disclosure without departing fromthe scope thereof

What is claimed is:
 1. A receiver unit of a wireless power transfersystem, the receiver unit comprising: a main receiver coil for receivinga wireless power signal having a first voltage from a transmitter unit;one or more auxiliary receiver coils for receiving the wireless powersignal having the first voltage from the transmitter unit; and anintegrated electronic component comprising: a receiver drive subunitcomprising: a main converter operatively coupled to the main receivercoil, wherein the main converter comprises a main output terminal; oneor more auxiliary converters operatively coupled to the one or moreauxiliary receiver coils, wherein the one or more auxiliary convertersare operatively coupled to each other to form an auxiliary outputterminal coupled in series to the main output terminal to form a commonoutput terminal; and a controller configured to determine one or morecircuit parameters of the receiver drive subunit, the controlleroperatively coupled to at least one of the main output terminal, analternating current terminal of the main converter, the common outputterminal, or an alternating current terminal of the common outputterminal.
 2. The receiver unit of claim 1, wherein one auxiliaryconverter of the one or more auxiliary converters is operatively coupledin parallel to another auxiliary converter of the one or more auxiliaryconverters.
 3. The receiver unit of claim 1, wherein one auxiliaryconverter of the one or more auxiliary converters is operatively coupledin series to another auxiliary converter of the one or more auxiliaryconverters.
 4. The receiver unit of claim 1, wherein each of the one ormore auxiliary receiver coils is operatively coupled to a correspondingauxiliary converter of the one or more auxiliary converters.
 5. Thereceiver unit of claim 1, wherein at least one of the one or moreauxiliary converters is at least one member selected from a groupconsisting of a passive rectifier, a hybrid rectifier, and an activerectifier.
 6. The receiver unit of claim 1, wherein the one or moreauxiliary receiver coils is disposed on the main receiver coil.
 7. Thereceiver unit of claim 6, wherein the one or more auxiliary receivercoils is disposed on at least one member selected from a groupconsisting of a first surface, a second surface, and a peripheral sideof the main receiver coil.
 8. The receiver unit of claim 1, wherein theone or more auxiliary receiver coils is at least one member selectedfrom a group consisting of a circular shaped, an oval shaped, a squareshaped, a triangular shaped, rectangular shaped, asymmetrical shaped,symmetrical shaped, and an elliptical shaped.
 9. The receiver unit ofclaim 1, wherein the one or more auxiliary receiver coils is disposedsymmetrically about the central axis of the main receiver coil.
 10. Thereceiver unit of claim 1, wherein at least one of the main receiver coiland the one or more auxiliary receiver coils is disposed on a ferritelayer.
 11. The receiver unit of claim 1, wherein the receiver unit isdisposed on a printed circuit board.
 12. The receiver unit of claim 1,wherein the main receiver coil and the one or more auxiliary receivercoils are resonant coils.
 13. The receiver unit of claim 1, wherein theintegrated electronic component further comprises: a communicationsubunit operatively coupled to the main receiver, the one or moreauxiliary receivers, and the controller; wherein the controller isconfigured to determine one or more circuit parameters corresponding toat least one of the common output terminal, the alternating currentterminal of the main converter, or the alternating current terminals ofthe plurality of auxiliary converters; and control at least thecommunication subunit based on the one or more circuit parameters. 14.The receiver unit of claim 13, wherein the communication subunit iscoupled to at least one member selected from a group consisting of thealternating current sensor of the main converter, the alternatingcurrent sensor of the one or more auxiliary converters, and the commonoutput terminal.
 15. The receiver unit of claim 13, wherein thesubstrate comprises a silicon wafer.
 16. The receiver unit of claim 13,wherein the integrated electronic component comprises a plurality offirst switches comprising at least one member selected from a groupconsisting of a diode, an insulated gate bipolar transistor, a metaloxide semiconductor field effect transistor, a field-effect transistor,an injection enhanced gate transistor, an integrated gate commutatedthyristor, a gallium nitride based switch, a silicon carbide basedswitch, and a gallium arsenide based switch.
 17. The receiver unit ofclaim 16, wherein the communication subunit comprises at least one of atleast one second switch and a demodulator.
 18. The receiver unit ofclaim 17, wherein the integrated electronic component further comprisesa third switch coupled across the common output terminal.
 19. Thereceiver unit of claim 13, wherein the integrated electronic componentis an application specific integrated circuit (ASIC), a very large-scaleintegration (VLSI) chip, a microelectromechanical system (MEMS), or asystem on chip (SoC).
 20. A wireless power transfer system comprising: atransmitter unit; and a receiver unit operatively coupled to thetransmitter unit, wherein the receiver unit comprises: a main receivercoil; a plurality of auxiliary receiver coils; an integrated electroniccomponent comprising: a receiver drive subunit comprising: a mainconverter operatively coupled to the main receiver coil, wherein themain converter comprises a main output terminal; and a plurality ofauxiliary converters operatively coupled to the plurality of auxiliaryreceiver coils, wherein the plurality of auxiliary converters isoperatively coupled to each other to form an auxiliary output terminalcoupled in series to the main output terminal to form a common outputterminal; a communication subunit operatively coupled to the receiverdrive subunit and a controller operatively coupled to at least one ofthe common output terminal, an alternating current terminal of the mainconverter, alternating current terminals of the plurality of auxiliaryconverters, or the communication subunit, wherein the controller isconfigured to: determine one or more circuit parameters corresponding toat least one of the common output terminal, the alternating currentterminal of the main converter, or the alternating current terminals ofthe plurality of auxiliary converters; and control at least acommunication subunit based on the one or more circuit parameters. 21.The wireless power transfer system of claim 20, comprising a fieldfocusing coil disposed between the transmitter unit and the receiverunit.
 22. The wireless power transfer system of claim 20, comprising aplurality of phase compensation coils configured to compensate a changein at least one of an impedance of the main receiver coil and a phaseangle of current flowing through the main receiver coil.
 23. Thewireless power transfer system of claim 20, wherein the transmitter unitcomprises: a transmitter coil; and a transmitter drive subunitoperatively coupled to the transmitter coil.
 24. The wireless powertransfer system of claim 23, wherein the plurality of auxiliary receivercoils is configured to compensate a misalignment between the transmittercoil and the main receiver coil.
 25. The wireless power transfer systemof claim 20, wherein the communication subunit comprises at least one ofa plurality of switches or a demodulator.
 26. The wireless powertransfer system of claim 25, further comprising a plurality of impedancecomponents, wherein a switch of the plurality of switches is coupled toa corresponding impedance component of the plurality of impedancecomponents.
 27. The wireless power transfer system of claim 26, whereinthe switch of the plurality of switches is operatively coupled to atleast one branch of the alternating current terminal of at least one ofthe main converter or the alternating current terminals of the pluralityof auxiliary converters via the corresponding impedance component. 28.The wireless power transfer system of claim 26, wherein the switch ofthe plurality of switches is coupled to the common output terminal viathe corresponding impedance component.
 29. The wireless power transfersystem of claim 25, wherein one switch of the plurality of switches iscoupled to another switch of the plurality of switches.
 30. A method ofa receiver unit of a wireless power transfer system, comprising:receiving a wireless power signal having a first voltage from atransmitter unit at a main receiver coil and at least one auxiliaryreceiver coil based on an alignment of the main receiver coil and theplurality of auxiliary receiver coils with a transmitter coil;generating a second voltage at a main output terminal of a mainconverter based on the first voltage; generating a third voltage at anauxiliary output terminal of a plurality of auxiliary converters basedon the first voltage; and transmitting a combination of the secondvoltage and the third voltage to a load.
 31. A method of operation of awireless power transfer system, the method comprising: determining, by acontroller, one or more circuit parameters corresponding to at least oneof a common output terminal, an alternating current terminal of a mainconverter, or alternating current terminals of a plurality of auxiliaryconverters, wherein the common output terminal is formed by connectingan auxiliary output terminal to a main output terminal of the mainconverter in series, wherein the auxiliary output terminal is formed byoperatively coupling the plurality of auxiliary converters of a receiverdrive subunit to each other; controlling operation of a communicationsubunit based on the one or more circuit parameters, wherein thecommunication subunit is operatively coupled to the receiver drivesubunit; receiving a wireless power signal having a first voltage from aa transmitter coil of a transmitter unit at a main receiver coil and aplurality of auxiliary receiver coils based on an alignment of the mainreceiver coil and the plurality of auxiliary receiver coils with thetransmitter coil, wherein the plurality of auxiliary converters isoperatively coupled to the plurality of auxiliary receiver coils and themain converter is operatively coupled to the main receiver coil; andgenerating a second voltage at the common output terminal.
 32. Themethod of claim 31, wherein controlling operation of the communicationsubunit comprises providing a gate control signal, by the controller, toa plurality of switches of the communication subunit based on the one ormore circuit parameters.
 33. The method of claim 31, further comprisingdemodulating information received from the transmitter unit by ademodulator of the communication subunit.
 34. An integrated electroniccomponent for a receiver unit of a wireless power transfer system, theintegrated electronic component comprising: a receiver drive subunit,wherein the receiver drive subunit comprises: a main converterconfigured to be operatively coupled to a main receiver coil, whereinthe main converter comprises a main output terminal; and a plurality ofauxiliary converters configured to be operatively coupled to a pluralityof auxiliary receiver coils, wherein the plurality of auxiliaryconverters is operatively coupled to each other to form an auxiliaryoutput terminal coupled in series to the main output terminal to form acommon output terminal; a communication subunit operatively coupled tothe receiver drive subunit; and a controller operatively coupled to atleast one of the receiver drive subunit, and the communication subunit,wherein the controller is configured to: determine one or more circuitparameters corresponding to the receiver drive subunit; and control atleast the communication subunit based on the one or more circuitparameters.